Arts, Science, and Engineering Students Driven by Solar Energy to the Finish Line
February 1, 2009
Two-hundred students with majors in the arts, sciences, and engineering teamed up for the construction of a solar-powered car to race from Plano, Texas to Calgary, Alberta. The competition required all vehicles run on 1,000 watts, cruise at highway speed and carry a driver 2,500 miles. Equipped with headlights and cruise control, the photo-voltaic powered car weighs 500 pounds and is 16 feet long and six feet wide. Constructed out of carbon fiber, the body is covered with thousands of gallium arsenide solar cells-- harvesting enough of the sun's energy to operate day and night.
ABOUT SOLAR CELLS: The solar cells on calculators and satellites are photovoltaic cells or modules: groups of cells electrically connected and packaged together. Photovoltaics convert sunlight directly into electricity. Photovoltaic cells are made of semiconductor materials like silicon. When light strikes the cell, a certain portion of the light is absorbed by the semiconductor material. The energy of the absorbed light knocks electrons in the semiconductor material loose, allowing them to flow freely. Photovoltaic cells also all have one or more electric fields that act to force the freed electrons to flow in a certain direction. This flow of electrons is a current. By placing metal contacts on the top and bottom of the photovoltaic cell, the current can be drawn off to be used. For example, the current can power a calculator. However, at a larger scale conventional photovoltaic panels made from silicon to provide electricity are expensive, and thus not cost-competitive with electricity from the power grid.
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